Patent Literature 1 describes a refrigerant evaporator. The refrigerant evaporator described in Patent Literature 1 includes a first heat exchange part and a second heat exchange part in which heat is exchanged with air that is a fluid to be cooled. The first heat exchange part and the second heat exchange part are arranged to oppose in a flowing direction of air. The first heat exchange part is divided into a first core part and a second core part in a direction perpendicular to the flowing direction of air. The second heat exchange part is also divided into a first core part and a second core part in a direction perpendicular to the flowing direction of air. The first core part of the first heat exchange part opposes the first core part of the second heat exchange part in the flowing direction of air. The second core part of the first heat exchange part opposes the second core part of the second heat exchange part in the flowing direction of air. The refrigerant evaporator described in Patent Literature 1 includes a pair of tanks disposed at the respective ends of the first heat exchange part in the vertical direction, and a pair of tanks disposed at the respective ends of the second heat exchange part in the vertical direction. Moreover, the refrigerant evaporator described in Patent Literature 1 includes a switch tank between the tank disposed below the first heat exchange part in the vertical direction and the tank disposed below the second heat exchange part in the vertical direction.
In the refrigerant evaporator described in Patent Literature 1, refrigerant flows from the tank above the second heat exchange part in the vertical direction to the first core part and the second core part of the second heat exchange part. The refrigerant flowing into the first core part of the second heat exchange part flows from the tank below the second heat exchange part in the vertical direction through the switch tank and the tank below the first heat exchange part in the vertical direction into the second core part of the first heat exchange part. The refrigerant flowing into the second core part of the second heat exchange part flows from the tank below the second heat exchange part in the vertical direction through the switch tank and the tank below the first heat exchange part in the vertical direction into the first core part of the first heat exchange part. The refrigerant flowing into the first core part of the first heat exchange part, and the refrigerant flowing into the second core part of the first heat exchange part are discharged through the tank above the first heat exchange part in the vertical direction.